open, throw away
胠 centers on opening something up, often with the sense of discarding or throwing away what is inside. The two given meanings connect through the idea of exposing or removing contents.
胠 combines the flesh radical ⺼ with 去, which likely contributes the sound. The exact historical development is uncertain, but the character may have originally referred to opening or exposing flesh.
The flesh radical ⺼ suggests something bodily, and 去 means 'to go away' or 'remove'. Imagine opening a wound to let out infection and throwing away the bad tissue.
For キョ, picture a key opening a lock and throwing away the old contents: key -> キョ, and the flesh part is exposed.